1. Field of the Invention
The present invention relates to agricultural planters, and, more particularly, to agricultural planters having wings with caster wheels that can be raised when in a working configuration and that can be lowered when in a transport configuration.
2. Description of the Related Art
Agricultural planters are commonly used implements to plant seeds in soil. An agricultural planter can include a chassis that carries one or more storage tanks full of seeds or other particulate that is to be spread on a field for planting, a hitch mechanism that attaches to a tractor or other implement pulled by a tractor, and a tool bar to which row units can be connected so that they are carried by the chassis.
Each row unit of the agricultural planter places seeds in the field. Typically, the row units are laterally arranged along a length of the tool bar so that as the planter is pulled across the field, each row unit plants seeds at predefined intervals along the path it is pulled across. To plant seeds, the row units perform four main operations as they are pulled: opening a trench in the soil; placing a seed into the formed trench at appropriate intervals; closing the formed trench to put soil on top of the placed seed; and packing soil on top of the seed to provide desirable soil contact with the placed seed.
To open a trench in the soil, a furrowing disc, also called an opening disc, presses into the soil and rotates, dislocating soil as it rotates to form the trench. Seeds are then placed in the trench at predefined intervals by a metering device which receives seeds from the main storage tank(s) or a row unit storage tank. One or more closing discs carried behind the furrowing disc are pressed into the soil and also rotate as the planter is pulled to cover the seeds placed in the trench with soil. Finally, a pressing wheel carried behind the closing disc(s) exerts pressure on the soil covering the seed to press the soil down onto the seed and provide good soil contact with the seeds. By having multiple row units working in unison as the planter is pulled across a field, many seeds can be effectively planted in an efficient manner.
Agricultural planters, like other agricultural implements, are often very wide, in order to efficiently perform their function over a large area in a given pass by the implement. In order to accomplish this, and yet to be transportable by road, they are often built to be folded into a transport configuration and unfolded into a working configuration. In order to fold into the transport configuration, often a set of wing sections rotate forward about vertical hinges until they are parallel with a main hitch bar of a center section of the agricultural planter. The center section is generally provided with a set of main wheels that can be raised when in the working configuration and lowered when in the transport configuration, and the wing sections are generally provided with wing section wheels that can be similarly raised and lowered.
In order to raise and lower the wing section wheels, hydraulic cylinders are used, typically located to the rear of the wing sections. However, locating the hydraulic cylinders to the rear of the wing sections uses valuable space needed for row units, and limits the placement and spacing of the row units. Further, locating the hydraulic cylinders to the rear of the wing sections limits the size and stroke of the hydraulic cylinders, so that less than optimal force and pressure must be used. The hydraulic cylinders may alternately be located to the front of the wing sections. However, this location interferes with folding the wing sections forward and close to the hitch bar of the center section of the agricultural planter.
What is needed in the art is a way to transition the wing section wheels from the working configuration to the transport configuration, without having hydraulic cylinders occupying space needed for row units to the rear of the wing sections, and without having the same hydraulic cylinders occupying space to the front of the wing sections which interferes with folding the wing sections forward and close to the hitch bar of the center section of the agricultural planter.
What is further needed in the art is a way for the wing section wheels to provide vertical support to the agricultural planter while in the transport configuration, while in the working configuration, and during the transition back and forth between the transport configuration and the working configuration.